This invention is concerned with separating members of a stack and is more particularly concerned with facilitating de-stacking of nested containers such as tapered drums.
Tapered drums, which may be fabricated from steel or plastic, for example, are used as containers for a variety of products. One of the advantages of the tapered drum is its nesting ability, so that when the drums are empty, they can be stacked up much like paper cups and shipped more economically than non-tapered drums.
A problem that occurs with tapered drums is that they tend to stick together when nested and stacked, making them difficult to separate. Each stack may contain eight to ten nested drums, for example, and is not easily handled manually. In a typical manual de-stacking process, a stack is pushed over onto a support, which may be comprised of old tires, for example, and then the drums are manually wrestled apart.
The machine and process of the present invention greatly facilitate the de-stacking of nested tapered drums, minimizing the amount of manual labor required.
Typically, several stacks of nested tapered drums, each stack including eight to ten drums, for example, are placed on a wooden shipping pallet. The drums in the stack are upside down, so that the wider ends face downwardly, and each drum has an exposed wider end portion.
In its preferred form, a machine of the invention comprises a base supported on wheels and an elongated cradle pivotally supported on an end of the base. The cradle is moved between upright and lay-down positions by an actuator.
With the cradle in its upright position, the machine is moved toward a stack of drums, and the stack is embraced by the cradle. First and second clamps mounted on the cradle embrace and grip a first drum:at the bottom of the stack and a second drum in the stack, respectively. The cradle is then moved to its lay-down position, carrying the embraced stack with it.
The first clamp is then moved away from the second clamp, to move the first drum away from the second drum in a de-nesting direction. Then the first clamp releases the first drum to permit the first drum to be separated from the stack.
Then the first clamp is moved toward the second clamp and the second clamp is released so that the stack can be moved along the cradle to align the second drum with the first clamp and a third drum of the stack with the second clamp. The clamps then grip the respective second and third drums, and the first clamp is again moved away from the second clamp to move the second drum away from the third drum. The first clamp then releases the second drum so that the second drum can be separated from the stack. This process is continued until all of the drums of the stack have been separated.